Apple's Siri also speaks on the iPhone 4, iPod touch 4G

The end of Siri's exclusivity on the iPhone 4S may be near. No, I'm not talking about Siri running on the purported Apple television set, but Siri on jailbroken iPhone 4 and -- possibly -- 3GS handsets.

The pair solved the problem using Troughton-Smith's code for the Siri port developed earlier this month, as well as software authentication tokens from a jailbroken iPhone 4S. Screenshots of the hack were posted to Twitter as well as two YouTube videos demonstrating the Siri port, one of which was given exclusively to 9-to5 Mac.

"I've tested pretty much every type of interaction you can make with [Siri on the iPhone 4]," Troughton-Smith told Macworld's sister title PC World in an interview via instant messenger. "It works just as well as the iPhone 4S, and I've seen it work even faster than it at times." The only feature that doesn't work, according to Troughton-Smith, is the iPhone 4S's so-called "raise to speak" feature that allows you to activate Siri's voice-command interface by raising the phone to your ear. The problem with raise to speak on Siri, Troughton-Smith says, is that it requires the new gyroscope in the 4S; it's not clear whether this could be solved. Google offers a similar raise to speak feature in its search application for iOS devices, including the iPhone 4 and 3GS.

Apple's Server Conundrum

Hackers have been trying to get Siri to work on iOS devices other than the iPhone 4S for several weeks now. But until the recent breakthrough, they had only the interface functioning while Siri voice commands on the iPhone 4 went unheeded. Siri relies on Apple's servers to do all the heavy duty processing of voice commands, and hackers hadn't yet figure out how to trick Apple into believing an iPhone 4 was actually an iPhone 4S. This problem, it appears, has now been solved.

It's not yet clear how Troughton-Smith and Paul solved the Siri-Apple server issue. Another pair of hackers were also working on the problem, and said their solution will rely on a third-party server to modify data sent between an unapproved Siri device and Apple's servers. Troughton-Smith declines to say whether his solution requires something similar, although I got the sense that it would not. Regardless, the Ireland-based hacker is keeping his solution fairly close to the vest for now.

"I can't quite go into details just yet," Troughton-Smith said. "The last thing I want is for Apple to lock this down before anybody's got a chance to see it." Part of the solution to Troughton-Smith's Siri port can be credited to the iPhone Dev Team's recent discovery of a preliminary jailbreak for the iPhone 4S. This made it possible to get an authentication token for Siri from Apple's latest iPhone. Troughton-Smith said he'd known for some time that his code for porting Siri to the iPhone 4 required an authentication token from the iPhone 4S, but without a jailbroken device, obtaining that token was difficult if not impossible. But after meeting with Paul, who had access to the DevTeam's unreleased jailbreak, the pair tried out Troughton-Smith's code and it worked almost right away.

Siri Unchained

It's not clear when the Siri port will be released. Troughton-Smith said he first wants to confirm it works properly, is secure, doesn't break other apps, and functions on iOS devices. It's likely the Siri port will be available after a public release of iPhone 4S jailbreak tools.

But even once the code is released, porting Siri to the iPhone 4 and other iOS devices won't be for the faint of heart. Troughton-Smith said he plans to release source code to the tools he made, but won't create a compiled program to help you do the port. In part, Troughton-Smith is leery of creating a specific jailbreak tool, because it may be grounds for Apple to sue for copyright infringement since a complete Siri hack tool requires modifying and distributing system files taken from an iPhone 4S.

For Troughton-Smith, the Siri hack isn't really about creating the final tool, but solving the technical challenge presented by moving Siri to other iOS devices. "I wanted to prove to myself that I could make Siri work," Troughton-Smith said. "To make it easy for everyone else I'll leave to whomever takes the reins after this."

The iPhone 4 may not be the only device to get some unofficial Siri love. Troughton-Smith plans to test his solution on the iPhone 3GS in November.